A liquid crystal display can show an image using electro-optical characteristics of a liquid crystal, which is injected into a space defined by two substrates. The electro-optical characteristics of the liquid crystals appear when electric power is applied thereto. Such a liquid crystal display is classified as one of a variety of types including twisted nematic (TN), super twisted nematic (STN), dynamic scattering mode (DSM), and the aforementioned PDLC, for example. Liquid crystal shutters are useful in various applications concerning the transmittance of light through an aperture in which it should be possible to switch the shutter between a low transmission state and a high transmission state, in response to a change in the electric influence.
PDLCs consist of micron-size droplets of low-molecular weight nematic liquid crystals dispersed in a polymer binder system. A PDLC material is sandwiched between substrates having a transparent conducting electrode such as indium tin oxide, to form a shutter. Upon application of a voltage across the electrodes of the shutter, a switching occurs from an opaque, high scattering state to a clear, transparent state. PDLC materials are formed by phase separation of low-molecular weight liquid crystals from a homogeneous solution with pre-polymer or polymer. The size, shape and density of the liquid crystal droplets depend on the techniques implemented. Major factors affect droplet size and density in the polymerization-induced phase separation process: materials type, relative concentration and curing temperature, for example. The curing temperature affects the rate of polymerization, viscosity of the polymer, diffusion rate of the liquid crystal and solubility of the liquid crystal in the PDLC system. With existing shutters, the transmission requirements are satisfied by use of a high driving voltage, which, in turn, increases power consumption requirements and makes compliance with ever more rigid environmental or green certifications difficult. Solutions continue to be required that improve transmission without the need for ever increasing driving voltages.